Field of the Invention
This invention relates to apparatus having an elongate pole with a tool mounted at a distal region of the elongate pole and, more particularly, to an apparatus for repositioning and operating the tool from a proximal region of the elongate pole.
Background Art
A multitude of different apparatus are currently in existence that utilize a tool mounted on an elongate pole that can be manipulated to facilitate placement of the tool at a desired location that is spaced from a region of the elongate pole that is held by a user. As one example, brush-type trimmers are commonly mounted at the distal region of an elongate pole, that may have a fixed or a variable length. At the proximal region of the pole, provision is made to conveniently grasp the apparatus in a manner that facilitates controlled user placement of the distal region at which the tool is located. Most commonly, this type of apparatus is utilized to permit the user to situate the tool at locations above those which are within the user's normal reach. As examples, the tool might employ an endless chain-type cutter, reciprocating trimmer blades, etc., which the user repositions to cut high limbs, or the like.
While manual-type tools are commonly used with this type of apparatus configuration, more recently a multitude of different powered tools have been devised for use on elongate poles. A drive for the tool is normally mounted at the proximal region adjacent to where the user controls the apparatus. The drive may be operated in any known manner, such as with an engine that operates on a combustible fuel, household current, a battery, etc. The drive transmits an operating force through a shaft that extends within the elongate pole.
The control mechanism for the drive typically consists of at least a throttle lever and an on/off switch that can be conveniently accessed by a user while gripping the apparatus at the proximal region for operation. In one form, with a straight grip construction, a user's hand extends graspingly around the lengthwise axis of the elongate pole. The throttle lever is pivotable about an axis that extends generally orthogonally to the central, lengthwise axis of the elongate pole. The throttle lever is situated to be movable by one of the user's fingers on the same hand that is grasping the apparatus at the proximal region of the elongate pole for operation.
In an alternative design, a “D”-shaped handle is provided with a curved portion that is spaced from the elongate pole and conveniently graspable by a user for operation. The throttle lever is commonly placed on the curved handle portion and is operated by the grasping hand in substantially the same manner as the earlier described embodiment.
To comply with industry regulations, and for purposes of safety, these powered apparatus are generally required to incorporate a safety switch that must be repositioned to allow the throttle lever to be moved in such a manner as to accelerate the drive. This avoids inadvertent movement of the throttle lever as might accelerate the drive.
Commonly, the safety switch is in the form of a lever that is pivoted or depressed. The safety switch is configured so that it is repositionable by a grasping hand of the user with the apparatus held thereby for normal operation. In one exemplary form, a user's one hand surrounds a grip portion with the palm region repositioning the safety switch. The user's fingers on the same hand are thus freed to operate the throttle lever.
One particular drawback with the straight grip or “D” handle grip configuration is that the user's reach with the tool is inherently somewhat limited. Additionally, use of an apparatus with this type of grip configuration may lead to considerable user fatigue.
With each of the straight grip and “D” handle grip configurations, the user is generally required to surround a region thereof that is generally parallel to the length of the pole axis. While holding and repositioning the apparatus in this manner, at some point as the user extends his/her operating arm upwardly, it becomes awkward or impossible to comfortably maintain a grip and simultaneously control the throttle lever and safety switch. Generally, this transition point occurs with the user's hand slightly above his/her head and the length of the arm angled slightly upwardly from horizontal.
Additionally, virtually the entire weight of the apparatus is borne by the user's hand in a manner that tends to hinge the wrist. Thus, a constant force must be exerted through the wrist to maintain the apparatus in the desired cutting position. After extended periods of operation, user fatigue may set in. This may lead to compromised work quality and, in a worst case, injuries.
The industry continues to seek out equipment designs that permit safe, controlled, and comfortable operation of a multitude of different tools and that may be mounted upon an elongate pole to provide the user with an extended reach.